We continue a week-long series on the top prospects the Atlanta Falcons are likely to consider at the sixth overall pick or higher with a look at Buffalo outside linebacker Khalil Mack.

One of Lou Tepper's best moments during his interactions with Khalil Mack had nothing to do with the football field.

The University of Buffalo defensive coordinator and linebackers coach recalled one night when he chatted with his star player for 15-20 minutes about nothing in particular. Tepper figured Mack had dropped by the office only because many of the student-athletes had night school.

``I just assumed he was there perhaps for one of his late classes,'' Tepper said. ``He really never said anything about it. The next day, one of janitors came by and said to me, `Coach, you're not going to believe this: Khalil Mack was here last night, cleaning the locker room.'

``He really views himself in a humble manner. If you were in our meeting room, you would never guess that he was 'the man' other than his physique. He helps young kids. He's positive. He's a special guy.''

Rare group: Tepper, who has more than 35 years of coaching experience and was once the head coach at the University of Illinois, has tutored a handful of special players in his lifetime. He would be exaggerating to say he immediately knew Mack would be one of those rare talents.

``I don’t think anybody could foresee that, and I would say the same for, you remember [former NFL players] Kevin Hardy or Simeon Rice,'' Tepper said. ``I don’t think anyone saw that early from them in their careers. And they all had the same typical junior year where they could have come out early and each of them probably would have been third or fourth-round draft picks. But each of them stayed. And each of them played themselves into being much higher.

``But Khalil had less football background. He only played a year in high school. He came in here at 210 pounds. When I came in, he had his hand in the dirt. He was a pass-rusher. The more that I saw him move, I really thought that he could play in space as well as rush the passer.''

There was a defining moment, in Tepper's eyes. It came on Oct. 20, 2012, in a game against Pittsburgh on a 41-yard screen play from Panthers quarterback Tino Sunseri to running back Rushel Shell.

``Khalil Mack pressured the quarterback, planted and took off and sprinted,'' Tepper recalled. ``It was against all odds. The chances that he had to make an impact on that play were not very high. But he full-sprinted down the field, tackled the running back at the 4-yard line, and we held them to a field goal. I think from that point on, the light turned on. And he became a much-more intense pursuer.

``His sophomore year, he did not understand coverage concepts because he did not have any experience in it. And he did not pursue at the level that we expect our guys to pursue. I think his junior year, both of those things turned positively.''

Check the film: If Tepper were to point to one entire game that epitomized Mack's career, it would be last year's season-opening, 40-20 loss to then-second ranked Ohio State. In the game, Mack finished with 2.5 sacks and a 45-yard interception return for a touchdown. Even in defeat, he earned respect.

``I know this: The film that turned his career around in terms of the scouts. ... He went from a third-rounder to a first-rounder in three hours at Ohio State,'' Tepper said. ``He was the most dominant player on the field. He beat their tackles with the pass rush. He beat their tight ends in the running game. He sacked [Braxton] Miller three times, and then he outran Miller to the end zone on the interception.''

Mack fought more than the Buckeyes that day. He battled the whole stigma about playing in the Mid-American Conference, although the MAC has produced a handful of reputable NFL players such as Ben Roethlisberger from Miami (Ohio) and Antonio Gates from Kent State.

``That was the knock on Khalil that the Illinois, LSU, Virginia Tech kids I coached did not have the same prejudice,'' Tepper said. ``Here’s a guy who broke two national records for tackles for losses and for forced fumbles, and yet there was that prejudice against the MAC. I don’t know that the scouts feel the same way that probably the media and fans do. I think the scouts know that there are credible players here. And I’ve coached in the SEC and the Big Ten.

``There are a lot of players here who can play at any level. You may have a few weeks were you’re facing somebody who’s not real strong. But let me tell you: That happens in the Big Ten, too. There were times when we lined up and we knew the left tackle wasn’t very good.''

Mack of all trades: The way Tepper talks about Mack, you would think he's capable of playing quarterback.

``I've had well over 20 NFL linebackers and three Butkus Award winners, but there have probably only been three or four who have been truly complete guys, and he’s one of those,'' Tepper said of Mack. ``He can play Mike, he can play Will, he can play Sam in a 4-3. He can put his hand down. He can play outside linebacker in a 3-4. He can play inside linebacker in a 3-4. He can do most everything, and there aren’t many of those guys. ... There aren’t many of them around.''

Tepper placed Mack in the same complete category as Mike Johnson (Virginia Tech), Bradie James (LSU), and Hardy (Illinois), all of whom played at least nine years in the NFL. Johnson and Hardy were both Pro Bowlers.

Tepper chuckles when questions are raised about whether Mack could fit in a 4-3 scheme, being that he seems better suited to play outside linebacker in a 3-4.

``I don’t think it matters,'' the coach said. ``He can play either of the three linebackers in a 4-3. He can play any of the four linebackers in a 3-4. And he can also put his hands on the ground. I don’t know what scheme there is that a guy like that he can’t play.''

High character: Tepper couldn't stop raving about Mack, the person.

``The most important thing to me is he is a guy of character,'' Tepper said. ``I wouldn’t want to wish the kind of money that he’s going to get on my son at his age, but he has a chance to withstand the temptations because of his faith and because of the way he’s been brought up. He’s humble. And I pray that he’ll stay that way.

``I text him every week. I have for quite a while. But I don’t text him about football at this point. It’s all about values and character. He’s going to have temptations that he could have only dreamed about. And I just pray that he can do the right things.''